1999 E430. The "ESP" warning came on in the Malfunction Indicator while traveling a straight section of highway at 60 mph. The "multiple malfunction" indicator (looks like two pages super-imposed on each other) came on also. The "ESP Warning Triangle" in the speedometer did not illuminate. The ESP switch on the console did not work. When I shut the key off (for a gas stop) the "BAS" warning came on in the Malfunction Indicator. When I restarted the car both had cleared. In the recent past the "ESP Warning Triangle" in the speedometer dial had come on briefly when making turns at moderate speeds (25-35 mph) in normal, not aggressive driving, on dry surfaces. Also, the "ESP Warning Triangle" in the speedometer dial had come on, and what sounded like the ABS system activated, during a turn in a cul-de-sac under the same seemingly ideal conditions. It seems as if the threshold for ESP intervention has somehow become too low. My dealer says the brake booster is at fault. Does this seem logical? I do not have any codes yet.

Check all tires for equal air pressure...
If all is well, the most common fail part is the brake lamp switch..

I understand the rear ABS sensor on the final drive unit can also fail giving ESP fits. I have never heard of a fault brake booster, anyone else?

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John Shellenberg
1998 C230 "Black Betty" 240K

http://img31.exs.cx/img31/4050/tophat6.gif

The ESP lamp went off in my mother's E430.

I checked her owner's manual, and it said that is voltage goes below a certain level, the lamp will be illuminated.

The fix was to turn the steering wheel from left to right so that the system could "relearn", or something to that effect.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

Yes the brake switch is a very common problem on the M Class also, check this http://forums.mbnz.org/forums/forums/thread-view.asp?tid=1166641&posts=14&hl=brake+switch out.

Don't know why the dealer would fault the booster without a proper diagnosis (or have they diagnosed it). But yes to answer John's question, there is a part in the booster for the BAS system which isn't available seperately, so it could need a brake booster because of this. I believe it's called the diaphragm travel sensor, could be wrong, maybe MB Stars will know for sure. There is one sensor which IS available seperately and one that isn't. (PS: Of course the one that IS available seperately I've never seen fail )
Sight unseen I'd more lean on the brake switch too, common on the 163, MORE common on the 210 it seems like. If it does this again if at all possible make SURE the brake lights are working. There are 2 sets of contacts and depending on which set fail you may not have operating brake lights, If EITHER set fail you'll get these warnings on the dash though. So you can get the warnings and may or may not have operating brake lights, so use caution.

Gilly

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Yes we have replace few of brake diaphragm travel sensor (control unit have to know how far the brake booster diaphargm travels)on 163 or 210 but also brake light switch is very common problems,the correct way dignosis BAS,ESP is read the code first then go after each code watch live data of the system to find out witch sensor cause problem today cars you must have the right tool to dignosis you can't compare 2004 car to 1994 car Mercede make a jiant step in ten years,just like your cell phone think about the cell phone you have ten years ago and the one you have right now what a different( phone E-mail,message,photo,on-line,sport news,weather,GPS,ring tone.......) by the way the travel sensor is available seperately. hope this help.

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MB STARS Master Guild Technician,17 years MB tech
14 years independent shop owner

Thanks for the help. This is what the dealer says: "Brake booster pressure switch short test performed - code C1406. Electrical system check/det condition - found brake booster pressure switch intermittantly open." They replaced the booster and a couple of ancilliary parts (not the travel sensor, though). Which brings me back to my question - does this make sense? I am just trying to understand the interface between the ESP and BAS systems and make sure that whatever the problem, it gets fixed right before my extended warranty expires next month. Also, maybe this thread will benefit someone else down the road. I did flog the car after I picked it up and it seems OK. But, the problem was intermittant, so who knows. Incidently, I had checked tire pressures, they were spot on. I checked the battery voltage and it was fine. I did not check the brake lights.

Go have code read see what codes in your BAS,ESP control unit ??? it will help you to diagnosis the system.

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MB STARS Master Guild Technician,17 years MB tech
14 years independent shop owner